For the purpose of this document, 'minor version' is in the sense of SemVer (major, minor, patch) and includes both major and minor releases. For projects that use date-based versioning, every release is a 'minor version'.
Python
initially released
36 months prior to our planned release date.numpy
initially released in the 36
months prior to our planned release date or oldest that supports the
minimum python version (which ever is higher)We will bump the minimum python and numpy versions as we can every minor and major release, but never on a patch release.
For python dependencies we should support at least:
We will only bump these dependencies as we need new features or the old versions no longer support our minimum numpy or python.
As these packages are only needed for testing or building the docs and not needed by end-users, we can be more aggressive about dropping support for old versions. However, we need to be careful to not over-run what down-stream packagers support (as most of the run the tests and build the documentation as part of the packaging process).
We will support at least minor versions of the development dependencies released in the 12 months prior to our planned release.
We will only bump these as needed or versions no longer support our minimum Python and numpy.
For system or c-dependencies (libpng, freetype, GUI frameworks, latex, gs, ffmpeg) support as old as practical. These can be difficult to install for end-users and we want to be usable on as many systems as possible. We will bump these on a case-by-case basis.